This invention relates to the field of percussive tools used in drilling. More specifically, the invention deals with a downhole jack hammer actuated by drilling fluid.
U.S. Pat. No. 7,073,610 to Susman, which is herein incorporated by reference for all that it contains, discloses a downhole tool for generating a longitudinal mechanical load. In one embodiment, a downhole hammer is disclosed, which is activated by applying a load on the hammer and supplying pressurizing fluid to the hammer The hammer includes a shuttle valve and a piston that are moveable between a first position and a further position. Seal faces of the shuttle valve and the piston are released when the shuttle valve and the piston are in their respective further positions to allow fluid flow through the tool. When the seal is releasing, the piston impacts a remainder of the tool to generate the mechanical load. The mechanical load is cycled by repeated movements of the shuttle valve and the piston.
U.S. Pat. No. 6,994,175 to Egerstrom, which is herein incorporated by reference for all that it contains, discloses a hydraulic drill string device that can be in the form of a percussive hydraulic in-hole drilling machine that has a piston hammer with an axial through hole into which a tube extends. The tube forms a channel for flushing fluid from a spool valve and the tube wall contains channels with ports cooperating with the piston hammer for controlling the valve.
U.S. Pat. No. 4,819,745 to Walter, which is herein incorporated by reference for all that it contains, discloses a device placed in a drill string to provide a pulsating flow of a pressurized drilling fluid to the jets of the drill bit to enhance chip removal and provide a vibrating action in the drill bit itself, providing a more efficient and effective drilling operation.